CN113195230A

CN113195230A - Method for transferring graphene out of a metal substrate

Info

Publication number: CN113195230A
Application number: CN201980078843.4A
Authority: CN
Inventors: M·埃萨曼; J·富尔克森; J·安德拉德
Original assignee: Research Foundation of State University of New York
Current assignee: Research Foundation of State University of New York
Priority date: 2018-11-30
Filing date: 2019-11-29
Publication date: 2021-07-30
Also published as: EP3887159A1; WO2020113174A1; KR20210095645A; US20220119262A1

Abstract

Methods for transferring graphene from a metal foil loaded graphene onto a substrate are provided. The method does not require chemical etching to remove the metal foil and provides more uniform graphene with improved electronic properties. The invention also provides a composition comprising graphene, an adhesive, and a substrate.

Description

Method for transferring graphene out of a metal substrate

Technical Field

The present invention relates to a method for transferring metal foil loaded graphene (graphene-on-metal foil) onto a substrate. The invention also relates to a composition comprising metal foil supported graphene and a substrate.

Background

Optically transparent and electrically conductive graphene thin films are important components in many devices, including transparent electrodes and conductive layers in displays, touch screens, windows, and solar cells; and emerging biomedical application kits, such as smart contact lenses. It is a challenge to design a film that is highly transparent to visible light while having little resistance to current flow. In addition to improved electro-optic performance, graphene films have desirable properties not achievable with today's materials, including flexibility, low cost, negligible light scattering, ultimate strength, and impermeability to water vapor. Furthermore, the fabrication process in any of the above applications requires controlled, uniform graphene growth and precise placement of graphene on the surface of various materials, while requiring development of cost-effective techniques for device fabrication.

For device fabrication, graphene is typically transferred onto a semiconductor, glass, or plastic substrate. Growing graphene onto metal foils (e.g., copper and nickel) via Chemical Vapor Deposition (CVD) can yield high quality graphene. However, a common method of transferring graphene onto the final target substrate involves spin coating and curing PMMA to the non-copper (graphene) side, followed by etching of the copper by floating in a copper etchant such as Ammonium Persulfate (APS) or ferric chloride. Etchant residues can lead to undesirable graphene contamination and also require that the target substrate be compatible with the etchant. Furthermore, etching away the metal prevents reuse of the metal for subsequent graphene growth. There is a need for graphene transfer and copper removal methods that do not rely on chemical etchants.

Disclosure of Invention

It is an object of the present invention to provide a method for transferring metal foil loaded graphene onto a substrate by a method that does not require the use of chemical etchants. It is another object of the invention to provide a method for removing metal foil from CVD grown graphene which avoids the use of chemical etching.

A method for transferring metal foil loaded graphene onto a substrate is described, the method comprising (i) coating the graphene side of the metal foil loaded graphene with a bonding solution or coating the substrate with a bonding solution, or both, the bonding solution comprising a solvent and a solute; (ii) contacting one or more binding solution sides of the metal foil-supported graphene-on-binding solution with the substrate or coated substrate; (iii) heating; (iv) cooling; and (v) removing the metal foil.

The invention further describes a composition comprising graphene, an adhesive and a substrate.

Drawings

Fig. 1 is a flow chart illustrating a method for transferring metal foil loaded graphene onto a substrate.

FIG. 2A is a microscope image of a PMMA/Gr surface on an acrylic substrate. FIG. 2B is the Raman spectrum of the PMMA/Gr surface. The large PMMA peak indicates the presence of a PMMA layer and acrylic substrate, and 2690cm^-1Peak at (2D peak) and 1580cm^-1The peak at (G peak) indicates the presence of graphene.

Fig. 3 is a photograph showing that 10 μ L of a 10% PMMA solution was placed on an acrylic substrate.

FIG. 4 is a photograph showing 30 μ L of a 40% PMMA solution spin coated onto a Cu/CVD Gr foil (Gr side up) at 3000rpm for 60 seconds.

FIG. 5 is a photograph showing a Cu/Gr/PMMA sample (Cu side up) placed on a 10% PMMA solution on acrylic.

Fig. 6 is a photograph showing that the sample was heated in an oven at 135 ℃ for 2 hours.

FIG. 7 is a photograph showing the sample being rapidly cooled in a refrigerator at-10 ℃ for 30 minutes immediately after being taken out of the oven.

Fig. 8 is a photograph showing the cooled sample after being taken out of the refrigerator. The PMMA layers fuse together and the Cu layer detaches from the Gr/PMMA.

Fig. 9 is a photograph showing the sample inverted to remove the Cu foil from the remaining substrate. No force is required to remove.

FIG. 10 is a photograph showing that a complete and uniform layer of PMMA/Gr remains on the acrylic after Cu removal.

Fig. 11 is a photograph showing that the PMMA/Gr layer remains translucent on the acrylic and the removed Cu foil remains intact.

Fig. 12 shows that the surface of the sample has a low defect density. Fig. 12A shows an optical microscope image of the sample surface after transfer, and fig. 12B shows a raman spectrum of the sample. At 1350cm^-1、1600cm^-1And 2700cm^-1D, G and 2D peaks were present, respectively, indicating successful graphene transfer. The ` D ` peak was very small, indicating that the defect density after transfer was very low. All other peaks correspond to solid PMMA substrates.

Fig. 13 shows graphene (a) on Cu sheets before transfer and 10-point test patterns on graphene (B) on PMMA/acrylic after transfer used in the procedure for obtaining raman data. To determine large area coverage of graphene on acrylic substrates, the above patterns were used and the results averaged.

Fig. 14 shows raman spectra at 10 test points of graphene (a) on Cu flakes before transfer and graphene (B) on PMMA/acrylic after transfer.

Detailed Description

The present invention provides a low cost, high quality transfer of CVD grown graphene from a metal foil growth substrate onto a selected target substrate by using a binder solution in combination with heating and cooling cycles. The described method allows for uniform contact between graphene and substrate even in the presence of unavoidable surface roughness on both the Cu foil/graphene sample and the substrate. This conformal contact is due to the presence of the bonding solution at the substrate-graphene interface. The binder contains a solvent that dissolves the surface layer on the substrate, ensuring conformal contact with the graphene. This contact in turn leads to complete separation of the graphene from the Cu foil after the cooling step. In contrast, standard methods require either stripping the graphene from the Cu foil or using a chemical etchant to dissolve the Cu foil, both of which result in poor graphene quality. The methods described herein produce graphene that is easily removed from the Cu foil and simply exfoliated even after a cooling step. This results in more uniform graphene with improved electronic properties.

Advantageously, the subject method does not require Cu etching at any step of the process, allowing the Cu foil to be reused by CVD for subsequent graphene growth cycles, thereby greatly reducing cost. The method of the invention avoids two main disadvantages of other graphene transfer processes, namely: (1) as the copper is etched away, the copper cannot be recycled for use in subsequent graphene growth cycles or general re-use, thereby significantly increasing costs; and (2) when the target substrate is a polymer, the polymer carrier layer may not be easily removed because both the substrate and the polymer carrier are easily dissolved by a set of similar solvents. The methods disclosed herein provide for etchant-free transfer of graphene from copper or other metal growth catalysts to a wide variety of polymer substrates without the need to apply a substantially continuous force (e.g., exfoliation).

The methods disclosed herein can also be used to transfer from a catalytic metal substrate (e.g., Cu) to a first substrate (e.g., PMMA) without etching, and then to transfer graphene from the first substrate to a target substrate of any composition by using, for example, a solvent and heat to selectively remove PMMA after transfer to the target substrate. In this embodiment, the advantages of catalytic metal substrate reuse are retained, but PMMA residues may be present on the graphene, as with all sacrificial-PMMA based transfer methods.

The term "graphene" as used herein refers to a polycyclic aromatic molecule formed from multiple carbon atoms covalently bonded to each other. The covalently bonded carbon atoms may form a 6-membered ring as a repeating unit, or may further include at least one of a 5-membered ring and a 7-membered ring. Thus, in graphene, covalently bound carbon atoms (typically with sp2 hybridization) form a monolayer. The graphene may have various structures, which may be contained according to the grapheneWith 5-membered ring and/or 7-membered ring. The term "graphene" as used herein may refer to a single layer (single layer graphene) or multiple layers (often referred to as multi-layer graphene or few layer graphite). Graphene can comprise 1-50 planar graphene sheets, for example, as a growth of multilayer graphene. The graphene layers in the multi-layer graphene each occupy about 340pm, and thus the multi-layer graphene (1-50 layers) may have a thickness of about 0.3nm to about 170nm, or otherwise about 1nm to about 30 nm. For LiC, relative to non-intercalated multi-layer graphene₆By way of example, these layer spacings increased by about 10% (from 340pm to 370pm per layer).

As used herein, the term "doping" refers to a process of preparing a carrier by providing an electron to or removing an electron from a portion of a conjugated pi-bonded orbital to provide conductivity to a conjugated compound (e.g., a polycyclic aromatic carbon compound). The process of adding new electrons or removing electrons is referred to herein as "doping".

The term "dopant" as used herein refers to an organic dopant, an inorganic dopant, or a combination comprising at least one of the foregoing.

In step 102, graphene is prepared by Chemical Vapor Deposition (CVD). In this process, graphene is formed on a catalytic metal substrate by decomposing a hydrocarbon precursor, such as methane, typically mixed with hydrogen at a suitable temperature (about 1000C-1100C) and pressure (about 1 mtorr-10 torr). (G.Deokar et al, Towards high quality CVD Graphene growth and transfer, Carbon,89,82-92 (2015); N.C.Bartlet and K.F.McCarty, Graphene growth on metal surfaces, MRS Bulletin,37, 1158-. Suitable metal substrates may be copper, nickel, platinum or iridium. To obtain a uniform single layer graphene sheet, the most common is to use a copper substrate. For multilayer graphene, copper, or more commonly nickel, is chosen. These particular metals are chosen because they all act as catalysts for graphene growth, and because they have a similar lattice spacing to graphene, they minimize lattice mismatch between the materials.

In another aspect, the graphene layer may comprise one or more dopants prior to contact with the substrate or coating. For example,the alkali metal dopant may optionally be intercalated into the graphene prior to treating the graphene with the binding solution. The alkali metal dopant can be Na, Cs, Li, K, and Rb, with Li, Na, and K being preferred. Graphene can be doped with an alkali metal dopant by, for example, contacting the graphene with a suitable electrolyte solution. The counter ion of the alkali metal can be any anion that is unreactive and stable under the conditions of graphene structure manufacture and use. Preferred counterions include ClO₄ ^-And PF₆ ^-. The electrolyte solution further comprises a solvent for the alkali metal salt. Preferred solvents include Ethylene Carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethylmethyl carbonate (EMC) and mixtures thereof. The alkali metal salt may be present at a concentration of 0.5 to 2M or sufficient to form MC₇₂、MC₃₆、MC₁₈、MC₁₂And/or MC₆(i.e., LiC)₇₂、LiC₃₆、LiC₁₈、LiC₁₂And/or LiC₆) Preferably MC₆Is present in the electrolyte solution. The electrolyte solution may be further contacted with a metal source, such as a metal foil, that maintains a high concentration of alkali metal in the electrolyte solution. In one embodiment, multilayer graphene is reacted with 1-1.2M LiPF₆A solution in 1:1wt EC/DEC (a solution of lithium hexafluorophosphate in ethylene carbonate and diethyl carbonate) was contacted while the electrolyte was in contact with the lithium metal foil. Intercalation of alkali metal ions into multilayer graphene (e.g., to form LiC₇₂、LiC₃₆、LiC₁₈、LiC₁₂And/or LiC₆). In this case, the intermediate layer preferably does not comprise further alkali metal ions. The intercalated graphene is then used in the methods and structures provided herein.

In the method of the present invention, the binding solution is coated on the graphene side of the metal foil-supported graphene (step 106), or the binding solution is coated on the substrate (step 104), or both the graphene side of the metal foil-supported graphene and the substrate are coated with the binding solution (steps 104 and 106).

In step 104, the substrate is coated with an adhesive solution. Preferred coating methods include spin coating, spray coating, drop casting, knife coating, or dip coating. The binding solution comprises a solute and a solvent. Representative solutes in the bonding solution include polyamides, polyimides, polyvinyl chloride, polyurethanes, polyvinyl ethers, polythioureas, polyacrylates, polycarbonates, polyesters, polyethylenes, polypropylenes, polystyrenes, PTFE, polyvinyl acetate, and fluoropolymers. Preferred solutes in the bonding solution include poly (methyl methacrylate), polyvinyl butyral, ethylene vinyl acetate, thermoplastic polyurethanes, polyethylene terephthalate, thermosetting ethylene vinyl acetate, polycarbonate, and polyethylene. Suitable solvents in the binding solution include water, chlorobenzene, acetone, methanol, N-methyl-2-pyrrolidone, tetrahydrofuran, dimethylformamide, hexane, toluene, isopropanol, acetonitrile, chloroform, acetic acid, 2-methoxyethanol, N-butylamine, and mixtures thereof.

Representative substrates include polyamides, polyimides, polyvinyl chloride, polyurethanes, polyvinyl ethers, polythioureas, polyacrylates, polycarbonates, polyesters, polyethylenes, polypropylenes, polystyrenes, nylons, polyvinyl acetates, and fluoropolymers. More preferred substrates include poly (methyl methacrylate), polycarbonate, polyethylene, polypropylene, polyester, nylon, and polyvinyl chloride.

In embodiments, the binding solution further comprises a dopant that increases the conductivity of the graphene. The dopant in the binding solution is used to increase the concentration of charge carriers in adjacent graphene layers. In further embodiments, the dopant may be an alkali metal salt. The alkali metal of the salt may be selected from Li, Na and K. The alkali metal salt is selected from the group consisting of MClO₄Or MI, wherein M is selected from the group consisting of Li, Na, and K. The concentration of M is in the range of about 2 wt.% to about 45 wt.% (w/w). In embodiments, the dopant is NaClO₄. In a preferred embodiment, the solute in the binding solution comprises between about 10 wt% and about 50 wt% poly (methyl methacrylate), and the solvent is selected from the group consisting of: n-methyl-2-pyrrolidone, tetrahydrofuran or dimethylformamide.

In step 106, the metal foil loaded graphene is coated with a bonding solution. In one aspect, the bonding solution coating the substrate may be the same or different than the bonding solution coating the metal foil loaded graphene. In embodiments, the binding solution further comprises a dopant that increases the conductivity of the graphene as provided above. In a representative embodiment, a 40% PMMA solution was spin coated onto a Cu/Gr foil at 3000rpm for 60 seconds. In one embodiment, approximately 30 μ L of a 40% PMMA solution was spin coated at 3000rpm onto a 1cm x 1cm area of Cu/Gr foil for 60 seconds.

In step 108, the product of step 104 and the product of step 106 are joined together. In particular, the bonding solution (e.g., PMMA) side of the product of step 104 is bonded to the bonding solution (e.g., PMMA) side of the product of step 106.

In step 110, the product of step 108 is heated. In embodiments, the heating step is performed at a temperature in the range of about 110 ℃ to about 160 ℃, and the temperature is maintained for a time in the range of about 5 minutes to about 4 hours.

In step 112, the product of step 110 is cooled. In one embodiment, the cooling step is performed at a temperature in the range of about-10 ℃ to about 20 ℃, and the temperature is maintained for a time in the range of about 5 minutes to about 4 hours.

In step 114, the copper foil is released. Advantageously, performing a cooling step after the heating step allows the metal growth substrate to be easily released from the graphene. For example, the sample may be inverted to remove the metal foil from the graphene, and minimal to no additional force is required for removal. In practice, there may be some adhesion of the polymer to the catalytic metal substrate, for example at one or more edges or defects of the structure where the polymer is in contact with the metal substrate rather than being separated by graphene. However, in the absence of such polymer-metal substrate contact, substantially no force is required to separate the graphene from the metal substrate, and the graphene can be separated from the metal substrate by inverting the sample. After removal, the metal foil can be reused for subsequent graphene growth.

Although illustrative embodiments of the present invention have been described herein, it is to be understood that the invention is not limited to those precise embodiments, and that various other changes and modifications may be affected therein by one skilled in the art without departing from the scope or spirit of the invention.

The described methods can be used to prepare compositions comprising metal foil supported graphene and a substrate.

The compositions may be used to manufacture electronic and/or optical devices, which may be in the form of complete devices, parts or sub-elements of devices, or electronic components, and the like. They may comprise a substrate having applied to at least one surface thereof a conductive coating comprising graphene. In embodiments, the electronic device is a flexible electronic device or a conductive window material.

Printed electronic devices can be prepared by applying the composition to a substrate in a pattern that includes conductive pathways designed to achieve a desired electronic device. The passageway may be solid, mostly solid, in liquid or gel form, or the like.

Other applications include, but are not limited to: passive and active devices and components; electrical and electronic circuits, integrated circuits; a flexible printed circuit board; a transistor; a field effect transistor; a micro-electro-mechanical system (MEMS) device; a microwave circuit; an antenna; a diffraction grating; an indicator; chipless tags (e.g., for theft protection in stores, libraries, etc.); security and anti-theft devices for retail, library and other venues; a keypad; a smart card; a sensor; liquid Crystal Displays (LCDs); a label; a lighting device; a flat panel display; flexible displays including light emitting diode, organic light emitting diode, and polymer light emitting diode displays; a back panel and a front panel of the display; electroluminescent and OLED lighting devices; a photovoltaic device comprising a backsheet; product identification chips and devices; a membrane switch; batteries, including thin film batteries; an electrode; an indicator; printed circuits in portable electronic devices (e.g., cellular telephones, computers, personal digital assistants, global positioning system devices, music players, game players, calculators, etc.); electronic connections established through hinges or other movable/bendable joints in electronic devices (e.g., cellular phones, portable computers, folding keyboards, etc.); a wearable electronic product; and circuits in vehicles, medical equipment, diagnostic equipment, instruments, and the like.

The electronic device may be a Radio Frequency Identification (RFID) device and/or a component thereof and/or a radio frequency communication device. Examples include, but are not limited to, RFID tags, chips, and antennas. The RFID device may be an ultra high frequency RFID device, which typically operates at a frequency in the range of about 868 to about 928 MHz. Examples of uses of RFID are for tracking shipping containers, products in stores, products in transit, and parts used in manufacturing processes; a passport; a barcode replacement application; an inventory control application; identifying the pet; controlling livestock; a contactless smart card; car key rings, etc.

The electronic device may also be an elastomeric (e.g., silicone) touch pad and a keypad. Such devices may be used in portable electronic devices such as calculators, cellular telephones, GPS devices, keyboards, music players, game consoles, and the like. They can also be used in myriad other electronic applications such as remote controls, touch screens, car buttons and switches, and the like.

Examples

Example 1: the graphene was transferred to an acrylic substrate.

Fig. 2-11 show examples of transfer of graphene to an acrylic target substrate. Acrylic resin was used as a target substrate (area about 1 cm)²) mu.L of a liquid PMMA (10 wt%, 12,000 daltons molecular weight) solution was placed on an acrylic substrate (see FIG. 3). In addition, 30 μ Ι _ of 40% PMMA solution was deposited onto the graphene side of 8mm x 8mm CVD grown graphene on copper foil and spun at 3000rpm for 60 seconds (see fig. 4). The Cu side of Cu/Gr/PMMA was placed up onto the above-described liquid PMMA/acrylic substrate (see fig. 5) such that the PMMA side of Gr was in contact with the PMMA side of the acrylic. The samples were then placed in an oven at 135 ℃ for 2 hours (see fig. 6). After removal from the oven, the samples were immediately placed in a refrigerator at-10 ℃ for 30 minutes (see fig. 7). The Cu foil was easily removed from the sample after removal from the refrigerator. Carefully flip the sample so that no additional force is required to remove the Cu foil (see fig. 8 and 9). After removal of the Cu foil, Gr/PMMAThe translucent layer remains on the acrylic surface (see fig. 10 and 11). Raman spectroscopy of the PMMA/graphene sample after transfer (see fig. 2B) confirmed that the graphene had been transferred onto the acrylic substrate.

Example 2

A1 mm thick acrylic substrate (Sigma Aldrich, GF28405122) was cut into 12.5mm by 12.5mm squares using a Boss Laser LS 1416 Laser cutter, then thoroughly cleaned in ultrasound for 20 seconds using an isopropanol bath, and treated with N₂And (5) drying. Immediately thereafter, they were placed in a glove box filled with argon gas for storage until use. Copper-loaded monolayer CVD Graphene from Graphene Platform was cut into 8mm x 8mm squares and placed between two clean microscope slides to ensure flatness, and then also placed into the same argon-filled glove box. Using a micropipette, 15 μ Ι of a 20% wt/V solution of poly (methyl methacrylate)/n-methyl-2-pyrrolidone (PMMA/NMP) was deposited in the center of the substrate and graphene was carefully placed on the polymer droplet. After repeating the procedure for several samples, they were placed on a hot plate at 150 ℃ and covered with a large beaker to simulate an oven. After 90 minutes, the samples were transferred to a sealed water-cooled Peltier refrigerator and also placed in a glove box specifically designed for this procedure.

Using the above mentioned Peltier refrigerator, the sample was directly lowered into the cooling chamber, covered with a lid, and cooled at a temperature of-1 ℃ for 15 minutes. Once completed, they were removed from the cooling chamber and allowed to reach ambient temperature (20 ℃) in the glove box for 5 minutes. The copper foil catalyst can be removed by tapping the substrate gently or by prying up a corner to loosen the Cu corner from contact with PMMA, thereby adhering the graphene to the surface of the acrylic.

The 10 points in a serpentine "2" pattern along the surface of the sample selected on graphene (a) on Cu sheets before transfer and graphene (B) on PMMA/acrylic after transfer were used in the procedure for obtaining raman data (fig. 14) (see fig. 13). To determine large area coverage of graphene on acrylic substrates, the pattern shown in fig. 13 was used and the results were averaged. The shape of the number '2' is used to ensure that the surface is adequately inspected and the points themselves are random, in addition to shape. The above results show that graphene is indeed deposited using this method. Once confirmed, a more in-depth study will be conducted whereby four additional samples are examined using a similar method. However, this time twenty points (also in the shape '2') were measured and within each of the twenty points there were five random points within a 100 μm x 100 μm area, totaling 125 points on each of the four samples. If 2D and G peaks are detected (similar to the spectra in FIG. 12), then the presence of graphene is determined. Sample 1 showed 69% graphene coverage, sample 2 showed 84% graphene coverage, sample 3 showed 62% graphene coverage, and sample 4 showed 76% graphene coverage. A total of 500 points were measured on the four samples, with graphene found on average 72.75% of the surface.

Our experimental results indicate the mechanism of the thermal release process. Graphene-polymer adhesion is relatively strong compared to graphene-copper adhesion, and the combined coefficient of thermal expansion mismatch results in separation of the copper foil in the thermal release methods described herein. Specifically, 0.232J/m is required²The thermal energy of (table 1) was used to raise the temperature of the system (graphene + copper + PMMA) from an ambient temperature of 20 ℃ to 150 ℃. Graphene typically shrinks by 0.12% relative to ambient at this elevated temperature. However, since the copper substrate expands 0.44% at 150 ℃ relative to the environment, the graphene is stretched 0.56%, resulting in 1.9J/m²Strain energy (table 2). This means that the total energy put into the system is about 2.1J/m². Previous experiments showed that the copper-graphene adhesion energy was in the range of 0.7J/m²To about 6J/m². This wide range can be explained by variations in sample preparation, as oxidation can significantly affect the adhesion between graphene and copper catalyst. In any case, 2.1J/m calculated from the heat release conditions²Falls within this range and is most likely sufficient to release the graphene from its metal growth substrate.

Table 1: estimation of the energy per unit area required to heat the Gr/Cu system from 20 ℃ to 150 ℃.

The final rapid cooling step allows for rapid removal of the copper foil from the desired substrate for further processing. Thus, the annealing temperature of 150 ℃ employed via this thermal release method is sufficient to remove the copper from the underlying substrate and once the copper foil is released, it can adhere to the liquid acrylic resin.

TABLE 2

Our process has advantages over other methods because the typical wet etching step of removing the copper foil catalyst from the graphene is eliminated, thereby preventing the transferred graphene from being contaminated by metal particles or residual etchant solution. In addition, using this method, the copper can be recycled and reused, corresponding to a substantial cost savings. Our technology produces uniform, continuous graphene surfaces on a wide variety of polymer substrates, which can be used for both rigid (thick substrates) and flexible (thin substrates) applications.

Claims

1. A method for transferring metal foil loaded graphene onto a substrate, wherein the method comprises:

(i) coating a graphene side of a metal foil supporting graphene with a bonding solution, wherein the bonding solution comprises a solvent and a solute;

(ii) contacting the bonding solution side of the metal foil-supported graphene upper bonding solution with the substrate;

(iii) heating;

(iv) cooling; and

(v) and removing the metal foil.

2. The method of claim 1, wherein the coating comprises spin coating, drop casting, blade coating, or dip coating.

3. The method of claim 1, wherein the method further comprises coating the substrate with a binding solution, wherein the binding solution comprises a solute and a solvent, and wherein the binding solution coating the substrate can be the same or different than the binding solution coating the metal foil supported graphene.

4. The method of claim 1, wherein the metal is selected from the group consisting of: copper, nickel, platinum and iridium.

5. The method of claim 1, wherein the solute in the binding solution is selected from the group consisting of: polyamides, polyimides, polyvinyl chlorides, polyurethanes, polyvinyl ethers, polythioureas, polyacrylates, polycarbonates, polyesters, polyethylenes, polypropylenes, polystyrenes, PTFE, polyvinyl acetates, and fluoropolymers.

6. The method of claim 5, wherein the solute in the binding solution is selected from the group consisting of: poly (methyl methacrylate), polyvinyl butyral, ethylene vinyl acetate, thermoplastic polyurethanes, polyethylene terephthalate, thermosetting ethylene vinyl acetate, polycarbonate, and polyethylene.

7. The method of claim 1, wherein the solvent in the bonding solution is selected from the group consisting of: water, chlorobenzene, acetone, methanol, N-methyl-2-pyrrolidone, tetrahydrofuran, dimethylformamide, hexane, toluene, isopropanol, acetonitrile, chloroform, acetic acid, 2-methoxyethanol, and N-butylamine.

8. The method of claim 1, wherein the substrate is selected from the group consisting of: polyamides, polyimides, polyvinyl chlorides, polyurethanes, polyvinyl ethers, polythioureas, polyacrylates, polycarbonates, polyesters, polyethylenes, polypropylenes, polystyrenes, nylons, polyvinyl acetates, and fluoropolymers.

9. The method of claim 8, wherein the substrate is selected from the group consisting of: poly (methyl methacrylate), polycarbonate, polyethylene, polypropylene, polyester, nylon, and polyvinyl chloride.

10. The method of claim 1, wherein the binding solution in step (i) further comprises a dopant that increases the conductivity of the graphene.

11. The method of claim 3, wherein the bonding solution coating the substrate further comprises a dopant that increases the conductivity of the graphene.

12. The method of claim 1, wherein the solute in the binding solution comprises between about 10 wt% and about 50 wt% poly (methyl methacrylate), and the solvent is selected from the group consisting of: n-methyl-2-pyrrolidone, tetrahydrofuran or dimethylformamide.

13. The method of claim 1, wherein step (iii) is performed at a temperature in the range of about 110 ℃ to about 160 ℃, and the temperature is maintained for a time in the range of about 5 minutes to about 4 hours.

14. The method of claim 1, wherein step (iv) is performed at a temperature in the range of about-10 ℃ to about 20 ℃, and the temperature is maintained for a time in the range of about 5 minutes to about 4 hours.

15. The method of claim 1, wherein the metal foil is reusable for subsequent graphene growth.

16. The method of claim 10, wherein the dopant is an alkali metal salt.

17. The method of claim 16, wherein the alkali metal salt is selected from the group consisting of: MClO₄Or MI, wherein M is selected from the group consisting of Li, Na, and K.

18. The method of claim 17, wherein the concentration of M is in the range of about 2% to about 45% by weight (w/w).

19. The method of claim 16, wherein the dopant is NaClO₄。

20. The method of claim 11, wherein the dopant is an alkali metal salt.

21. The method of claim 20, wherein the alkali metal salt is selected from the group consisting of: MClO₄Or MI, wherein M is selected from the group consisting of Li, Na, and K.

22. The method of claim 21, wherein the concentration of M is in the range of about 2% to about 45% by weight (w/w).

23. The method of claim 20, wherein the dopant is NaClO₄。

24. A composition comprising (i) a metal foil loaded graphene, (ii) a substrate, and (iii) one or more bonding solutions, wherein the one or more bonding solutions are disposed between the metal foil loaded graphene and the substrate.

25. The method of claim 24, wherein the metal in the metal foil is selected from the group consisting of: copper, nickel, platinum and iridium.

26. The composition of claim 24, wherein the binding solution comprises a solute and a solvent.

27. The composition of claim 26, wherein the solute in the binding solution is selected from the group consisting of: polyamides, polyimides, polyvinyl chlorides, polyurethanes, polyvinyl ethers, polythioureas, polyacrylates, polycarbonates, polyesters, polyethylenes, polypropylenes, polystyrenes, PTFE, polyvinyl acetates, and fluoropolymers.

28. The composition of claim 27, wherein the solute in the binding solution is selected from the group consisting of: poly (methyl methacrylate), polyvinyl butyral, ethylene vinyl acetate, thermoplastic polyurethanes, polyethylene terephthalate, thermosetting ethylene vinyl acetate, polycarbonate, and polyethylene.

29. The composition of claim 26, wherein the solvent in the binding solution is selected from the group consisting of: water, chlorobenzene, acetone, methanol, N-methyl-2-pyrrolidone, tetrahydrofuran, dimethylformamide, hexane, toluene, isopropanol, acetonitrile, chloroform, acetic acid, 2-methoxyethanol, and N-butylamine.

30. The composition of claim 24, wherein the substrate is selected from the group consisting of: polyamides, polyimides, polyvinyl chlorides, polyurethanes, polyvinyl ethers, polythioureas, polyacrylates, polycarbonates, polyesters, polyethylenes, polypropylenes, polystyrenes, nylons, polyvinyl acetates, and fluoropolymers.

31. The composition of claim 30, wherein the substrate is selected from the group consisting of: poly (methyl methacrylate), polycarbonate, polyethylene, polypropylene, polyester, nylon, and polyvinyl chloride.

32. An electronic and/or optical device comprising the composition of claim 24.

33. The electronic device of claim 32, wherein the electronic device is a flexible electronic device.

34. The electronic device of claim 32, wherein the electronic device is a conductive window material.